Scotty.. you know the G80 locking diff from the sound of it. My dealership (prior truck) didn't believe that it wasn't working. Took the manager (first name basis ya know) out for a spin and he couldn't tell. Getting frustrated and it being winter, I drove past the service door (his face dropped) doing about 50mph toward the back of their lot. Right over the curb and up to the huge pile of snow. "Uh..you might get stuck" he says. I replied, "if that happens, you'll agree there is an issue because three tires should be spinning if I get stuck. Plus you have how many trucks here..we'll pull it out". Nose it into the bank and stuff the pedal. I say "open your door, your tire isn't spinning" I tell him to get out of the truck and look, ***** wanted me to let the truck back down off 50mph before he'd get out.
End result.. it got fixed.
Other result of many issues at that dealer...not one of the service writers or manager would come within 20 feet of me. I never threatened or touched anyone. Was a bit angry looking though.
